Corrections and clarifications:This story has been updated to reflect fact that Basaglar can’t be used in an insulin pump.

Many parents of diabetic children and adults suffering with type 1 or type 2 diabetes are bracing for changes in insurance coverage of their insulin next year, as prices of the vital medication continue to soar.

Higher insurance deductibles and changes in the prescription brands covered by some insurers are raising concerns among some people with diabetes.

CVS Caremark, a pharmacy benefit manager (PBM), will no longer cover the insulin brand Lantus in favor of a new biosimilar version, Basaglar. Biosimilars are considered the generic versions of "biologic" drugs that are based on natural sources.

The company also announced a program last week to further keep diabetes costs down, following a similar move in August by competitor Express Scripts.

Diabetes is an epidemic in the United States, affecting nearly 10% of the population or about 29 million people, according to the Centers for Disease Control and Prevention. Of those, more than 8 million people are undiagnosed.

Type 1 diabetes — often still called juvenile diabetes — can occur when people are children or adults. Type 2 diabetes is becoming more common with the increase in obesity and sedentary behavior.

Prices for Humalog and many insulin brands have increased from about $300 to $500 between January 2013 to October 2016, according to drug discount search company GoodRx. Lantus increased about 60% — from $240 to $380 — in the same time period, GoodRx says.

Henry Anhalt is a pediatric endocrinologist and chief medical officer of the T1D Exchange.(Photo: T1D Exchange)

"It’s definitely unfortunate prices are going up so much and impacting the people who need it to stay alive," says Henry Anhalt, an Englewood, N.J., pediatric endocrinologist. "But I think a big part of the problem is how much (insurers) cover and how much they fight you."

The amount of insulin a diabetes patient needs every day depends on what they are going to eat, how much they will exercise and their stress level, says Anhalt, chief medical officer of the T1D Exchange, which is researching ways to better manage diabetes and runs an online community for people with type 1 diabetes.

Changes in the formularies — the lists of drugs covered by insurers and pharmacy benefit managers (PBMs) — make many patients anxious, says Anhalt,

But Troyen Brennan, a physician and chief health officer at CVS Caremark, says he's heard "very little complaint with regard to stress levels." Basaglar has been proven to be "exactly equivalent if not slightly better," he says.

Patients who have a bad reaction to a change in insulin can request an exception to the formulary, Brennan adds.

Kristina Blake has type 1 diabetes and insurance through the city of San Diego, her previous employer. Her deductible has increased by 400%, so she "will be dealing with the retail prices next year," she says.

Because she will always need insulin, Blake says, "I accept that I am a "cash cow."

Until insurers started fighting back against price increases by raising deductibles and changing formularies, the companies' reactions to price hikes tended to get more attention than the actual prices. That's starting to change.

In the past four years, Blake says, her receipts show the price for three vials of Humalog nearly quadrupled, adding that it's not "a new and improved medication."

"That's disgusting," she says.

Drugmakers say price increases are necessary to fund innovation and note that the portion of the price going to PBMs and wholesalers is confidential. The PBM trade group says the industry has little choice but to fight back.

"Employers, unions and government programs that offer these benefits don’t have much choice but to spend their resources on competitively priced (medications) that offer the same or better value," says Mark Merritt, CEO of the trade group Pharmaceutical Care Management Association.

Nearly $5,000 is spent on average per diabetes patient every year on medical expenses that could have been avoided if patients had taken their diabetes medications as prescribed, according to Express Scripts.

Improperly treated diabetes can lead to loss of limbs, kidney function and vision.

Mindy Bartleson, 24, was diagnosed with type 1 diabetes when she was 7 and lost good insurance coverage when her father died of cancer when she was 12.

"I remember what it was like to be floating around trying to get on a low-income insurance," says Bartleson, a program assistant with the College Diabetes Network. "After I gradated from college and got to switch to a new insurance company, my stress level went down because I wasn’t in survival mode."